Liquid Biopsy in Modern Oncology: Advances, Challenges, and Future Perspectives in Early Cancer Detection, Minimal Residual Disease, and Dynamic Patient Monitoring.

purpose of reviewLiquid biopsy has emerged as a minimally invasive approach to overcome the limitations of tissue biopsy in oncology. This review aims to synthesize recent advances in its clinical applications, particularly in early cancer detection, therapeutic monitoring, and minimal residual disease (MRD), while discussing current challenges, regulatory perspectives, and future directions. RECENT

findingsCirculating tumor DNA (ctDNA), circulating tumor cells (CTCs), extracellular vesicles, and epigenetic markers are the most extensively studied biomarkers, in which clinical trials such as TRACERx and DYNAMIC have demonstrated that ctDNA monitoring enables earlier detection of recurrence and guides adjuvant therapy decisions more precisely than standard imaging. Commercially validated assays, including Guardant360 CDx, FoundationOne Liquid CDx, and Epi proColon, have received regulatory approval, reflecting growing clinical adoption; however, limitations persist, including reduced sensitivity in low-tumor burden settings, technical variability between platforms, and the risk of false positives from clonal hematopoiesis. Ongoing research highlights the promise of multi-omic approaches and the integration of artificial intelligence to improve sensitivity, capture tumor heterogeneity, and provide predictive insights into treatment response and resistance. Liquid biopsy represents a paradigm shift in precision oncology by enabling real-time, longitudinal tumor profiling. Although significant barriers remain, such as cost, accessibility, and lack of standardization, technological innovations and large-scale validation studies are paving the way for its routine clinical integration.